The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Infrastructure mode networks typically include a discovery server and/or a coordination server for discovery and connection setup between mobile devices. The discovery and coordination servers obtain information regarding network connected peers and application-specific information. The discovery and coordination servers are typically located at an access point. A peer-to-peer (P2P) network generally does not include a discovery server, a coordination server, or an access point. Mobile devices (or peer devices) of a P2P network communicate directly with each other.
Discovery of peer devices within a P2P network may include active discovery scanning or passive discovery scanning. Active discovery scanning refers to a first mobile device transmitting probe messages to peer devices (i.e., other mobile devices). The first mobile device may transmit probe messages to join a P2P network and/or to communicate with another mobile device. A probe message includes, for example, a basic service set identifier (BSSID) and data rates of the first mobile device. Peer devices operating in a “listen” mode (at the time a probe message is sent by the first mobile device) may respond to the probe message by sending a probe response signal.
Passive discovery scanning refers to a first mobile device that temporarily operates as an access point and transmits beacons at periodic intervals. The first mobile device generates the beacons to allow other mobile devices to join a P2P network and/or to communicate with the first mobile device. A beacon includes, for example, a BSSID, time synchronization information, power saving information, and capability information associated with the first mobile device. During each of the periodic intervals, the first mobile device operates in a “listen” mode. While operating in the listen mode the first mobile device is typically powered ON and “listens” or waits for response signals from peer devices. Examples of active and passive scanning are described in IEEE 802.11 standards.
Mobile devices typically operate in a “sleep” mode to conserve power. While operating in a sleep mode a mobile device may be partially powered down or fully powered down. Mobile devices that perform active and/or passive scanning transition between operating in a listen mode and a sleep mode. As an example discovery process, a mobile device may operate in a listen mode at least 50% of the time that the mobile device is operating in a discovery enabled mode (i.e., at least 50% duty cycle). The mobile device may operate in a sleep mode the remainder (or other 50%) of the time that the mobile device is in the discovery enabled mode.